#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int main(int argc,char* argv[])//mycmd -a或mycmd -b
{
  if(argc!=2)
  {
    printf("can not execute\n");
    exit(1);
  }
  if(strcmp(argv[1],"-a")==0)
  {
    printf("hello a!\n");
  }
  else if(strcmp(argv[1],"-b")==0)
  {
    printf("hello b!\n");
  }
  else{
    printf("default!\n");
  }
  return 0;
}
